Sensor tag may combat 'friendly fire' incidents

Portland, Ore. - Fratricide-the act of killing one's own soldiers, also called "blue-on-blue" incidents-can now be largely prevented through the use of a radar tag sensor developed at Sandia National Laboratories (Albuquerque, N.M.), according to engineers there.

"We think we can help prevent friendly fire incidents with our sensor, but there are still many hurdles to get over before they become a part of the U.S. military procurement cycle," said engineer Lars Wells, leader of the group that invented the device.

In some recent conflicts, the casualties from "friendly fire" incidents have been higher than those from enemy fire.

During a recent test of the radar tag sensor, the Sandia National Laboratories engineers showed that it can return a synthetic radar echo when targeted by radar from U.S. aircraft, thereby alerting the aircraft not to target that "friendly" position. Properly installed on all U.S. and coalition military vehicles and eventually on individual soldiers themselves, the device's inventors believe it can virtually eliminate friendly fire from aircraft (but not artillery) during combat. The sensor is slated to make its debut before U.S. Army procurement officials this fall.

"So far we have verified that the sensor works, even with multiple radars from multiple aircraft, and by this fall we will have ruggedized and miniaturized it enough for vehicles. Individual soldiers will come later," said Wells.

The Army hopes the sensor, dubbed Athena, will work to lower or even eliminate the percent of wartime casualties that are due to fratricide. Historically, that number stands at 10 to 15 percent. In particular, 24 percent of the 146 American battle deaths during Operation Desert Storm were from friendly fire and 15 percent of the 480 wounded were also due to fratricide.

"We can't reveal all the details about our sensor-for security reasons-but I can tell you what it is not-it's not a radio transmitter," said Wells.

Instead of transmitting a radio signal that aircraft must integrate with the dozens of other data streams already overloading their electronics systems, the Athena sensor only reacts when it is targeted by friendly aircraft radar. Instantly, Athena recognizes that it has been targeted and returns a synthetic radar echo that only U.S. and coalition aircraft can decode, identifying it as a friendly position.

Aircraft radar works by sending out a quick pulse, then reads the reflections received from objects on the ground. The Athena sensor responds to radar "pings" by producing a synthetic radar echo that hostile aircraft will not be able to decode. U.S. and coalition aircraft will not only be able to separate the Athena signal from the normal reflections from tanks, trucks and other battlefield objects, the recent test also proved that quick-acting electronics can mark the position on a pilot's screen with an icon that pictures the type of friendly position there.

These icons, which are also fed back to ground-based control rooms, should also enhance situation awareness on the battlefield. In the future, for example, commanders will be able to account for all soldiers by using polling radars that identify their current positions, allowing them to attack instead of pulling back because of fear that friendly soldiers may be nearby.

Funding for the project began at the Department of Energy's Non-proliferation Office, but is now sponsored by the Army's Communication Electronics Research, Development and Engineering Center.

This fall the Army will stage a large exercise for high-ranking Army officers that demonstrates the Sandia National Laboratories tag system as well as several other technologies designed to prevent fratricide and improve situational awareness.